1. Field of the Invention
The invention relates to a protective corrugated plastic pipe. Furthermore, the invention also encompasses a protective corrugated plastic pipe structure with a slotted outer pipe and, preferably, a slotted corrugated pipe inside.
2. Description of the Prior Art
In the known prior art, protective plastic corrugated pipes or tubes and arrangements are used, for instance, to lay fibreglass cable in the earth. Corrugated piping such as this and corrugated pipe structures or arrangements are also used for various liquids such as petrol and for gases.
A drawback of the prior art is shown when it comes to laying fibreglass cable in the earth. The protective piping is bent to such a point that the fibreglass cable is bent beyond the permitted bending radius. This can lead to the optical signal transmission being disturbed. Indeed, a fibreglass cable which has been bent in this way might allow no light through at all.
Moreover, corresponding pipes, i.e. those required for supplying fuel, may be similarly malformed such that they are no longer able to carry the necessary amount of fuel.
Furthermore, it can happen that a pipeline in the form of a corrugated pipe can also be used to carry fuel once that pipe is given a certain shape. The prior art dictates that it is necessary here to heat corrugated pipes such as these after they have been manufactured. They then assume the required shape upon cooling and during the second heating retain that shape. This could, for instance, be knee shaped or it might assume some other form.
Therefore, making available a plastic corrugated pipe or a corresponding structure which tackles the drawbacks listed above is the task in hand according to the invention. Above all, a protective plastic corrugated pipe or a protective plastic corrugated pipe structure should be created. These should be made in such a way that fibreglass cable which is to be protected by the plastic corrugated pipe or structure can be fitted so that the light getting through is not affected in any way.
The advantages which can be achieved according to the invention come about due to a protective plastic corrugated pipe in which at least some of the corrugated flanks have been fitted with extensions, which extend from one corrugated flank in the axial direction of the pipe towards a neighbouring flank. This means that it is possible that the fibreglass cable, which is in a protective plastic corrugated pipe, cannot be bent at the desired place to any point exceeding that room for manoeuvre which the extension has facilitated. This, of course, is a positive effect as it prevents the cable from breaking. Also, when the fibreglass cable has been buried in the earth in a protective plastic corrugated pipe, and movements due to thickening earth because of rain etc. occur the pipe supplies sufficient resistance in accordance with the invention. This again means that the fibreglass cable, which has been placed in the corrugated pipe, cannot be bent. Once more, this complies with the invention.
The protective plastic corrugated pipe or structure can, according to the invention, be used to protect fibreglass cables or other wiring elsewhere too. For instance, it can be used in a car engine or the like.
Likewise, a protective plastic corrugated pipe or structure with characteristics which correspond to the invention can also protect the fibreglass cable against those external threats which might occur through the environment. The long slotted outer corrugated pipe connected to the corrugated pipe inside, which holds a fibre class cable, facilitates this. The structure is formed at the desired place such that deforming or damage of the cable in the structure according to the invention is highly improbable under normal conditions. Strictly speaking, it is sufficient for the outer corrugated pipe to have the proper structure, especially since the corrugation rings on the corrugated pipe inside grip the rings on the outer corrugated pipes from inside. This provides further resistance against any deformation.
Regarding the piping, the protective plastic corrugated pipe can be slotted in an axial direction. This means that cables in general and fibre glass cables in particular can be easily fitted into the protective plastic corrugated pipe and, if necessary, can be easily replaced. Here, the long slotted pipe can be an outer pipe which can take a selected, similarly long slotted internal pipe. This internal pipe or tubing might be in the form of a non-corrugated hose.
If the long slotted internal pipe is also completely corrugated, it may be seen as an alternative to the external pipe or it may facilitate the additional function of adding to the stabilisation of the pipe vis-à-vis external forces which might deform it. Adding the necessary extensions does this.
The extensions can be fitted even if they are only to be found on the outside pipe, on both pipes or only on the external pipes. Here, they would be fitted at angles on the circumference. Nevertheless, it is especially advantageous if the extensions are connected one after another so that there is a sequence of parallel axial connections. Here, the desired properties of the protective plastic corrugated pipe, with characteristics which are in accordance with the invention, can be reliably utilised.
In order to prevent any deformation taking place due to external factors, despite the changes which have been made to the protective plastic corrugated pipe, at least two angled extensions should be attached symmetrically to the circumference of the pipe. They should be fitted in an axial position behind one another. It is especially advantageous if three extensions are placed symmetrically. The three points form three independent levels, which in turn facilitate stabilising the surfaces over the three extensions. These can have an advantageous effect in offsetting any potential damage, especially to fibreglass cables. Similarly, the same can be said for four and more extensions which are spread evenly over the circumference.
If a particular task is foreseen for the pipe according to the invention, e.g. carrying fuel, then there may be some advantage if the pipe were to assume a particular form and if it were to keep this form. Here, it would be advantageous if the extensions according to the invention were notched sections and the corresponding grooves opposite or at the end of these sections were provided as sections where the notches are clicked into place. If, e.g., there are four rows of notched sections and four corresponding sections which the notches are clicked into, then it is possible by clicking the notched sections into place to produce, for instance, a narrow knee. This will then stay in place because the process is mechanically stabile. Heat treatment, which the prior art requires here, and additional work are no longer required. On the other hand, this plastic corrugated pipe variation according to the invention is very flexible when applied, because the shape of the corrugated pipe can indeed be changed once it has been fitted in a certain way and, indeed, once changed it can keep the new form for as long as necessary.
It can also be an advantage if the internal pipe has notched extensions and/or notched sectionsxe2x80x94sections where the notches are clicked in and if the corresponding outer pipe has notched extensions and/or notched sectionsxe2x80x94sections where the notches are clicked into place. This will enable them to be clicked into one another. Where there is a slotted pipe for a structure, this process facilitates the internal pipe being more securely attached to the outer or external pipe.
The extensions can both be on the flank side of the corrugations so that the extension from one corrugation connects with the extension of another corrugation.
The cross section in the invention or structure according to the invention can be arbitrary. It can be oval, square, triangular or diagonal.
Certainly, it is also possible to put a notched section on the corrugation on each of the axial sides and to put a section for accepting the notched part on the opposite side of the same corrugation. This means that the intention would be to attach it to a connecting corrugation. However, it would be more practical from a technical point of view if there were only one notched section on a corrugation and a section for slotting it in on the other corrugation.
For technical reasons, corrugated pipes are manufactured in a xe2x80x9ccorrugatorxe2x80x9d. This means that it may be necessary to shape the notched section, the section which the notches go into and the extensions in general, either in the shaping plane of the mould or in the moulding channel. Another possibility would be to perform the shaping in the level, which is vertical to the shaping plane. If the respective extensions, notched extensions or similar are formed outside these planes then the protective plastic corrugated pipe is difficult to separate from the moulds or can only be separated with a great deal of force. This might lead to the corrugated pipe product being damaged.
With reference to the protective plastic corrugated pipe structure in accordance with the invention, there are also variations which might be considered favourable. For instance, if the internal corrugated pipe had a safeguard against being twisted, such as a safeguard which slots into the slot on the outer pipe, and which is directed in the same axial direction as the extension structure originally was, and like this structure covers at least two of the neighbouring corrugations. Through this structure, which because of its cross-sectioned nature resembles a lens, shaping of the total structure can likewise be regulated or limited. This in turn facilitates limiting the flexibility of the structure further, and ensures that even where there is excessive pressure on the structure, the structure will not be deformed to such an extent that the fibreglass will be damaged. The protective plastic corrugated pipe structures according to the invention will prevent any deformation in areas, for instance, where there are strong earth movements, quakes, landslides etc.
Here too, at least two preferably lens shaped structures, which are connected by at least two corrugations, can be formed. However, a corrugation trough between the structures that follow.
In total, there should be at least three and preferably four structures over the total structure. They should be distributed uniformly, at angles, over the surface of the structure. One of these structures will then preferably serve at the same time as a safeguard against twisting, for the internal corrugated pipe vis-à-vis the external corrugated pipe.